O'Sullivan & Hilliard's The Law of Contract (2018 8 ed). p. 200.
In cases where it is clearly a common inn or, indeed, where it is uncertain whether it is a common inn or a private hotel, I am of opinion that [2.] a notice in these terms would not exempt the hotel company from liability for negligence but only from any liability as insurers. Indeed, even if it were clearly not a common inn but only a private hotel, I should be of the same opinion. [1. Red] Ample content can be given to the notice by construing it as a warning that the hotel company is not liable, in the absence of negligence. As such it serves a useful purpose. It is a warning to the guest that he must do his part to take care of his things himself, and, if need be, insure them. [3. Green] It is unnecessary to go further and to construe the notice as a contractual exemption of the hotel company from their common law liability for negligence. I agree that the appeal should be dismissed.
Red underline : What does "ample content can be given to the notice" mean?
Sentence 2 : Denning judges that the notice wouldn't "exempt the hotel company from liability for negligence but only from any liability as insurers". But how can content be "ample" (Question 1) if it doesn't exempt liability for negligence?
Green underline : Why "unnecessary to go further"?